I believe older java versions are already incompatible with newer jvms. I couldn't find it explicitly stated but i'd be surprised if 1.4 code worked 100% corre

I believe older java versions are already incompatible with newer jvms. I couldn't find it explicitly stated but i'd be surprised if 1.4 code worked 100% correct on a 1.7 jvm. My experience so far is that the list of incompatibilities (http://www.oracle.com/technetwork/java/javase/compatibility-417013.html#jdk7 http://www.oracle.com/technetwork/java/javase/compatibility-...) between versions makes it nearly impossible to just drop code between versions. It will run, but often implementation details have changed causing significant bugs. Your mileage may vary